1. Field of the Invention
The present invention relates to an output power control device of an engine.
2. Description of the Related Art
In aircraft using reciprocating internal combustion engines to drive their propellers, the engines are driven at their maximum output during takeoff since the greatest propulsion is required at the time of takeoff. Once the aircraft switches to steady flight, however, the engines are driven at an output of about 80 percent of the maximum output, for example. During steady flight, the amount of fuel consumption is usually reduced by operating the engines using a lean air-fuel mixture. If, however, the engines are operated using the lean air-fuel ratio when maximum engine output is demanded, such as during takeoff, the cooling action of the fuel becomes insufficient, so the problem arises of overheating of the engine valve system and pistons.
There is known an internal combustion engine for aircraft use designed so that when a maximum output is demanded of an engine, the air-fuel mixture is made rich to improve the cooling action of the fuel and prevent overheating of the engine valve system and pistons and at the same time improve the maximum output of the engine (see U.S. Pat. No. 4,693,670). In this aircraft internal combustion engine, when a power lever provided at the pilot's seat is pushed in the direction of the engine maximum output and passes a certain position, the air-fuel mixture is switched from a lean mixture to a rich one.
However, when the air-fuel mixture was suddenly changed from a lean mixture to a rich mixture or from a rich mixture to a lean one at a certain position of the power lever, there was the problem of a shock due to the sudden change of the engine output. Further, if the engine output changes suddenly with respect to a position of the power lever in this way, the problem arises that the aircraft can not tail other aircraft well.